Art of making bleaching compound.



of Harrisburg, in the State of Pennsylvania,

UNITED STATES Patented September 22, 1903.

PATENT OFFICE.

ART OF MAKING BLEACHING COMPOUND SPECIFICATION forming part of LettersPatent No. 739,448, dated September 22, 1903.

Application filed January 14, 1902.

To all. whom it may concern:

Be it known that I, MARcUs RUTHENBURG,

have invented certain new and useful Improvements in Bleaching Compoundsand in the Art of Making the Same, whereof the following is aspecification.

My invention relates to aqueous solutions of chemicals adapted forbleaching cellular substances, such as paper-pulp'and the like; and itis the object of my invention to obtain the maximum bleaching efiectfrom a given quantity of chemical employed.

The process of making my improved compound consists in mixing, indefinite proportions, anaqueous solution of sodium chlorid with anaqueous solution of hydrated oxid of calcium and subjecting the mixtureto the action of an electric current until the product is a compoundhaving the peculiar characteristics hereinafter specified and comprisinga double chlorin salt of sodium and calcium.

In the conduct of my process aforesaid I have found it convenient toemploy an aqueous solution comprising twenty per cent. of so; diumchlorid, mixed with an aqueous solution containing ten per cent. ofhydrated oxid of calcium and to subject the mixed solution to the actionof an electric current from electrodes supplied with current in theproportion of one-half ampere per square inch of the electrode-surfaceexposed to the solution and at a pressure of three volts until thechemical components of the mixture are reduced to the state ofhypochlorites, which condition maybe ascertained by the usualarsenious-acid test. I

I am aware that it has been hitherto known that a bleaching agent may beproduced by electrolyzing a solution of sodium chlorid per. se. However,one eifect of such electrolysis is to liberate a large percentage ofchlorin fromthe solution, with consequent loss of bleaching efficiencyof the latter.

My present invention is advantageous in that the production of ableaching agent from the sodium chlorid is effected by the elec--trolysis without dissipating the chlorin as heretofore, the chlorinbeing taken up by the hydrated oxid of calcium, forming ad ditionalsoluble chlorin salt in the solution,

Serial No.89,"744. (N0 specimens.) I

and thus augmenting the bleaching capacity of the latter. It is also tobe noted that the addition of the 'oxid of lime 'to the solutionincreases the conductivity of the latter, and thus effects aconsiderable saving in the amount of the electric current employed toeffect the electrolysis.

Although I prefer to employ-the oxid of calcium because of its low cost,it is to be noted that an equivalent effect may be produced in thesolution by the additionof the oxids of magnesium, lithium, aluminium,sodium, and potassium.

It is to be noted that the electrolyzed compound produced by the'processherein set forth is characterized by greater bleaching efficiency than amere mixture of hypochlorites of sodium and calcium of equivalent oxi- 7dizing capacitythat is to say, of two compounds whose oxidizing capacityis determined to be equal (by the arsenious-acid test) the electrolyzedcompound manifests greater bleaching efficiency, is more rapid in itseffects, and for a given degree of whiteness ob tained the electrolyzedcompound detracts less from the weight of the material treated. It isalso to be noted that although my improved compound is weakened inbleaching effect by continued use it may be restored to its initialefficiency by the addition of suitable proportions of the chemicalsaforesaid and renewed subjection to the action of the electric current.

In view of the variable nature of the chem- I icals named I do notdesire to limit myself to the employment of the particular percentagesthereof above specified. It is also to be understood that the desiredelectrolysis of the mixture may be effected by more or less exposure toan electric current of dimensions differing from those above specified.l

I claim- I 1. The hereinbefore-described process of making a bleachingcompound, which consists in making an aqueous solution comprising twentyper cent. of sodium chlorid; mixing with said solution an aqueoussolution containing ten per cent. of hydrated oxid of calcium;subjecting the mixed solution in a free state to the action of anelectric current supplied in the proportion of one-half ampere persquare inch of the electrode-surface, exposed to the solution, and at apressure of three Volts, until the chemical components of the mixtureare reduced to the state of hypochlorites, substantially as set forth.

2. The hereinhefore described process of making a bleaching compound,which consists in making an aqueous solution comprising twenty per cent.of sodium chlorid; mixing with said solution an aqueous solutioncontaining a less percentage of the oxid of an alkaline; subjecting themixed solution in a free state to the action of an electric currentsupplied in the proportion of one-half ampere per square inch of theelectrode-surface, exposed to the solution and at a pressure of threevolts until the chemical components of the mixture are reduced to thestate of hypochlorites, substantially as set forth.

In testimony whereof I have hereunto signed my name, at Philadelphia, inthe State of Pennsylvania, this 13th day of-January,

MARCUS RUTHENBURG. \Vitnesses:

ARTHUR E. PAIGE, E. L. FULLERTON.

